1. Field of the Invention
This invention relates to an apparatus and method for sorting semiconductor devices.
2. Brief Description of the Art
Various types of integrated circuit devices have evolved since the development of the semiconductor. Such semiconductor devices have innumerable applications in industry and commerce. In the manufacture of semiconductor devices, it is known to first create a strip which constitutes an integral unit containing numerous semiconductor devices within the strip. For example, a strip of semiconductor devices may have 40, 80, or 100 semiconductor devices contained within the strip. The strip of semiconductor devices are then taken to a cutting apparatus where the strip is cut into numerous units separating and singulating out each individual semiconductor device. Once the strip has been singulated into individual semiconductor devices, it is known in the industry to sort and transfer the singulated semiconductor devices to various locations for further processing. For example, it is known in the art to transfer these singulated semiconductor devices to JEDEC trays, bulk bins, shipping tubes, or a tape and real apparatus where the singulated semiconductor devices are then transferred to another location for further processing.
Various semiconductor device handlers or transfer systems have been developed within the semiconductor device industry for transferring (or off loading) the singulated semiconductor devices to predetermined locations for further processing. For example, it is known to have an automated mechanism which picks up an individual singulated semiconductor device after it has been cut from the strip and then places the singulated semiconductor device in the appropriate location such as a JEDEC tray or bulk bin. The robotic arm then returns and picks up the next singulated semiconductor device and moves it to the predetermined location for unloading the semiconductor device at the appropriate location for further processing. The problem with such systems is that by picking up individual semiconductor devices one at a time, such devices are slow and inefficient in off loading the singulated semiconductor devices for further processing. Further, such a system does not provide for any intelligent sorting of the semiconductor devices in an application where the semiconductor devices have previously been tested for quality purposes.
For example, it is known in the industry to test an entire strip of semiconductor devices so that quality information can be obtained for each individual semiconductor device located on the strip. However, the current sorting apparatuses for off loading the singulated semiconductor devices from the strip location to the predetermined off load location for further processing do not utilize any of the quality information obtained regarding the individual semiconductor devices on the strip. Rather, these current off loading systems simply transfer all of the singulated semiconductor devices, one at a time, to a predetermined off load location without regard to any quality information known about the particular semiconductor device. In other words, all the xe2x80x9cgoodxe2x80x9d and xe2x80x9cbadxe2x80x9d semiconductor devices are offloaded to the same location. This then requires further testing or visual inspection of different characteristics of the singulated semiconductor devices to sort the xe2x80x9cgoodxe2x80x9d and xe2x80x9cbadxe2x80x9d devices.
Other systems for off loading singulated semiconductors devices involve simply xe2x80x9cdumpingxe2x80x9d the entire strip of singulated semiconductor devices into a bulk bin for transfer to a location for further processing. Numerous disadvantages with this type of system include the fact that the semiconductor devices are not retained in an orientation for ease of handling for further processing. Another disadvantage is that the devices are not sorted based on any quality information related to the specific semiconductor devices.
As noted above, it is known in the semiconductor device industry to test a strip of semiconductor devices prior to singulation of the individual semiconductor devices. In this regard, it is known in the industry to create an electronic strip map which contains address or location information and quality information (i.e., such as xe2x80x9cgoodxe2x80x9d or xe2x80x9cbadxe2x80x9d) specific to each individual semiconductor device on the strip. For example, a strip of semiconductor devices can be submitted for testing as a whole, prior to singulation, and quality information can be obtained for each specific semiconductor device on the strip. An electronic strip map is then created which contains specific address and quality information related to each individual semiconductor device on the strip. One industry organization, Semiconductor Equipment and Materials International (SEMI), has developed draft standards for the creation of electronic strip maps for strips of semiconductor devices. However, even with the creation of electronic strip maps related to strips of semiconductor devices, the information contained in the electronic strip map has not been utilized in the industry to increase the efficiency of off loading singulated semiconductor devices from a strip for further processing.
What is needed is a method and apparatus for sorting singulated semiconductor devices which is fast and efficient in transferring the singulated semiconductor devices from the singulated location to a predetermined off load location, such as a JEDEC tray, bulk bin, etc., for further processing.
The present invention provides a method and apparatus for sorting semiconductor devices which is able to efficiently off load a strip of singulated semiconductor devices to various predetermined locations for further processing. The invention further provides an apparatus and method which is able to pick up a plurality of singulated semiconductor devices and intelligently transfer the plurality of singulated semiconductor devices to various predetermined locations for further processing.
According to one embodiment of the present invention, there is provided a method for sorting semiconductor devices for processing where semiconductor devices have been singulated from a strip containing a plurality of semiconductor devices while still retaining the semiconductor devices in a form corresponding to their positioning on the strip. Additionally, an electronic strip map has been created corresponding to the strip of semiconductor devices and the electronic strip map contains address and quality information related to each individual singulated semiconductor device. The method includes moving a pickup device to a location adjacent the singulated semiconductor devices and selectively picking up a first plurality of singulated semiconductor devices based on the electronic strip map information related to the singulated semiconductor devices. The method further includes moving the semiconductor devices that have been picked up to a predetermined location based on the electronic strip map information for the specific semiconductor devices that have been picked up and unloading the first plurality of semiconductor devices at the predetermined location.
In one embodiment, the method further includes a step of visually inspecting the first plurality of semiconductor devices which have been picked up by the pickup device for transfer to the predetermined location. The visual inspection confirms that the semiconductor devices picked up correspond to the first plurality of semiconductor devices that were selected to be picked up based on the electronic strip map information. In addition, the step of visual inspection can further include a quality inspection of the semiconductor devices that have been picked up and based on the quality inspection, modify the predetermined unload location for any semiconductor device that is determined to have a different quality characteristic than the quality characteristic indicated by the electronic strip map information for that particular semiconductor device.
In one embodiment, the method of sorting semiconductor devices further includes returning the pickup device to the singulated semiconductor units that were not previously picked up and selectively picking up a second plurality of singulated semiconductor devices based on the electronic strip map information related to the singulated semiconductor devices and moving the second plurality of semiconductor devices that have been picked up to a predetermined location based on the electronic strip map information for the specific semiconductor devices that have been picked up and unloading the second plurality of semiconductor devices at the predetermined location.
Pursuant to another embodiment of the present invention, an apparatus is provided for sorting semiconductor devices where the semiconductor devices have been singulated from a strip containing a plurality of semiconductor devices and where an electronic strip map has been created containing address and quality information related to each individual singulated semiconductor device. The apparatus includes a semiconductor device carrier adapted for receiving a plurality of singulated semiconductor devices where the semiconductor device carrier includes a base portion having a top surface divided into a plurality of cavities sized to receive an individual singulated semiconductor device with each of the cavities including a vacuum aperture therein.
In this embodiment, the apparatus further includes a first transfer mechanism including a rotatable arm adapted for releasably securing the semiconductor device carrier to a portion of the arm. The first transfer mechanism is in selective connection with a vacuum source and the vacuum apertures in the cavities of the semiconductor device carrier. The arm of the first transfer mechanism is movable to a first location adjacent the strip of singulated semiconductor devices where the singulated semiconductor devices are secured in the corresponding cavities in the semiconductor device carrier under the force of the vacuum source applied to the vacuum apertures. The arm is then movable to a second location. The apparatus further includes a second transfer mechanism which releasably engages the semiconductor device carrier and disconnects it from the first transfer mechanism to moves the semiconductor device carrier to a carrier unload position.
The apparatus further includes a semiconductor sorting mechanism including a robotic arm movable between the carrier unload position and predetermined locations for unloading the semiconductor devices. The robotic arm includes a pickup head including a plurality of vacuum ports connected to a vacuum source. The pickup head vacuum ports are selectively able to extend down from the pickup device and pick up a plurality of singulated semiconductor devices and release the semiconductor devices at a predetermined location. The sorting mechanism includes a controller for controlling movement of the robotic arm from the carrier unload position to the predetermined locations and for controlling the vacuum ports of the pickup head for selectively picking up semiconductor devices from the semiconductor device carrier under the force of the vacuum source and releasing the semiconductor devices with assistance of compressed air when the pickup head of the robotic arm has reached a predetermined location. The controller of the semiconductor sorting mechanism receives the electronic strip map information regarding the address and quality of the singulated semiconductor devices located on the semiconductor device carrier and directs the pickup head to selectively pick up a plurality of semiconductor devices from the semiconductor device carrier and transfer the semiconductor devices to a predetermined location to unload the semiconductor devices at that location.
In one embodiment, the apparatus further includes a vision module located adjacent the semiconductor device carrier at the carrier unload position wherein the vision module includes a visual inspection system that visually inspects the semiconductor devices after they have been picked up by the pickup head of the sorting mechanism.
According to another embodiment of the present invention, there is provided a method for transferring a plurality of semiconductor devices arranged in a matrix format where the spacing between the adjacent rows and columns of semiconductor devices is represented by xcex1 and xcex3 respectively, with the rows constituting the x-axis and the columns constituting the y-axis, to a receiving apparatus having a plurality of receptacles in a matrix format for receiving the semiconductor devices where the spacing between the adjacent rows and columns of receptacles is xcex4 and xcex2 respectively, where xcex1 and xcex3 are different from xcex4 and xcex2. The method includes the step of providing a pickup device having a plurality of vacuum ports attached to a vacuum source for picking up a plurality of semiconductor devices with the vacuum ports arranged in a matrix format so that when the pickup head has picked up semiconductor devices, the spacing between the adjacent rows and columns of semiconductor devices on the pickup head is represented by xcex1 and xcex2 respectively.
The pickup device moves adjacent to the plurality of semiconductor devices so that the row of vacuum ports having xcex1 spacing are in alignment with the rows of semiconductor devices having xcex1 spacing. The first column of vacuum ports is positioned vertically above the first column of semiconductor devices and the first column of vacuum ports extend down to pick up the first column of semiconductor devices. The pickup device moves along the x-axis so that the second column of semiconductors devices is vertically aligned with the second column of vacuum ports and the second column of vacuum ports extend down to pick up the second column of semiconductor devices. The pickup head continues to move along the x-axis so that each successive column of vacuum ports in the pickup device is vertically aligned with each successive column of semiconductor devices to pick up the successive columns of semiconductor devices. The pickup device then moves to the receiving apparatus so that the columns of vacuum ports in the pickup device having xcex2 spacing between the semiconductor units are in alignment with the columns of the receptacles of the receiving apparatus having xcex2 spacing. The first row of vacuum ports holding semiconductor devices is positioned vertically above the first row of receptacles and the pickup device then releases the first row of semiconductor devices from vacuum ports under the force of compressed air into the first column of receptacles.
The pickup device moves along the y-axis so that the second row of vacuum ports of the pickup device is in vertical alignment with the second row of receptacles and the pickup device releases the semiconductor units into the corresponding receptacles. The pickup head continues to move along the y-axis so that each successive row of vacuum ports of the pickup device is in vertical alignment with each successive row of the receptacles of the receiving apparatus and the pickup device releases each successive row of semiconductor devices held by the pickup device under the force of compressed air into each successive row of receptacles in the receiving apparatus.